Resilient folding rule hinge



Dec. 29, 1953 H. M GAssTRoM ET AL 2,663,940

RESILIENT FOLDING RULE HINGE Filed Sept. 15, 1951 w 151 O O ,a ANDJQHN E. GASSTROM 'W557i ma@ ATTORNEY Patented Dec. 29, 1953 RESILIENT FOLDING RULE HINGE Herman M. Gasstrom, Pelham,

trom, Mount Vernon,

Rule Mfg. Corp.,

and John E. Gass- N. Y., assignors to Eagle New York, N. Y.

ApplicationI September 13, 1951, Serial No. 246,408 Claims. (Cl. 33-119) l 'The present invention relates to hinges and pivoting means for folding rules and the like, and particularly to a resilient folding rule hinge. g The main object of this invention is to provide a hinge for a folding rule that is sufficiently re' silient in its action to allow of easy opening and Y closing of the rule with a minimum of wear.

Another object of the invention is to provide a folding rule hinge that has a coil spring producing a desired amount of operative friction and ensuring proper locking of the rule in the fully open and closed positions.

A further object is to have such a folding rule hinge that is compact and not likely to get out of order and therefore durable.

It is also an object to produce a special resilient hinge for folding rule that is relatively simple and yet entirely practical in construction, while being reasonable in cost.

An important object is, of course to provide a resilient folding rule hinge of the character indicated that is not only effective in actual use by a workman, but completely avoids any increase in external dimensions over conventional hinges for the same purpose.

Other objects and the advantages of the invention will appear in further detail as the specification proceeds.

In order to facilitate ready comprehension of this invention for a proper appreciation of the salient features thereof, the invention is illustrated on the accompanying drawing forming part hereof, and in which:

Figure 1 is an' enlargedv fragmentary elevation of a portion of a folding rule showing the mutually hinged portions of two rule sections extended in open position and joined by a-resilient hinge made according to the present invention and ernbodying the same in a practical form;

Figure 2 is an exploded view of the same rule sections and the joint involved, with the rule portions in section and certain hinge portions in perspective view to clarify actual form and nature of the parts;

Figure 3 is an elevation similar to that of Figure 1 of the upper or left rule section in partly assembled condition; Y y

Figure 4 is another elevation showing the other or opposite side of the same rule section appearing in Figure 3;

Figure 5 is an enlarged longitudinal section taken on line 5-5 in Figure 1 showing the rule -sections initially assembled;

Figure 6 is a similarsection of the same rule sections fully assembled and finished irl construe.. tion and relationpof parts; and

Figure 7 is a vertical section taken on line 1 1 in Figure 6.

Throughout the views, the same reference numerals indicate the same or like parts.

In folding rules, the hinge between sections is. of course an important feature of the rule involved, and especially is it important that the hinge offers no more than a minimum desirable amount of friction when the sections are to be opened or closed. Such rules should have a certain resilient resistance to being opened or closed that is just enough to cause them to give way when proper force is applied manually to open or close the sections, but should not require undue effort to do this nor any unreasonable strain that might break the rule.

Of course, more or less at leaf springs have been enclosed in' rule joints but'they are limited in strength and likewise have certain disadvantagesv that it is desired to eliminate by a ynew principle of construction. Upon considering this problem, it has become apparent that it should be possible to introduce a coil spring of no more than a few turns into a folding rule joint in order to reap the benet of the superior resilience of such a spring in opening and closing such a rule. AS a result, a special resilient folding rule joint has been successfully produced that will be explained in full detail in the following.

Hence, according to the practice of this invention, and referring now again to the drawing, a folding rule, generally indicated at 8 primarily includes two rulesections 9 and I0, representing a large number of sections hinged together in a series to form a complete rule. Of the two sections shown, merely the end portions appear, with the ends II and I2 overlapping. Upon end portion I I is secured a metal hinge or strike plate having longitudinal anchoring side flanges I3, I3, the plate itself being noted I4 and having a pair of aligned male locking projections I5, I5. The rule section 9 has a pair of short bevels I6, I6 along the edges of its end II with the flanges I3, I3 of plate I4 gripped upon these bevels to anchor the plate in position on the rule.

In similar fashion, a second hinge or strike plate I'I has a pair of anchoring side flanges I8, I8 along its edges gripping the bevels I 9, I9 along the sides of rule section I0 at its end I2 to retail this section and plate assembled. This plate I'I, however, in correspondence with the male projections I5, I5 has female seats 2B, 2i) into which the projections I5, I5 t in extended open position or closed retracted position of the rule sections in more or less conventional manner.

In order to center the two plates and provide hinge means, a downwardly projecting integral nipple 2l is formed on plate I4 and extends down into a corresponding hole 22 in plate I'I, rule section I having a slightly smaller corresponding hole 23 through which nipple 2| extends to a short distance below the upper surface of this rule section so that the nipple engaging in the hole 22 of lower plate I'I will serve to accurately pivot the two plates with respect to each other. It may be well to note that the upper rule section 9 in its end portion II has an enlarged bore 24 concentric with nipple 2 I for a purpose which will immediately be explained.

When the rule sections are assembled, a long grommet 25 having an upper head or retaining flange 26 extends down through hole 24 in section 9 and through nipple 2|, lower plate vII and hole 23 in lower section Ii] and into a bottom nishing plate 21 having two anchoring teeth 28, 28 driven into the wood `of section Ill. In preliminary assembled condition as shown in Figures 2 and 5, the lower end lor grommet 25 is simply straight as rst introduced into the iinishing plate, but when the parts are finished and iinally locked into permanent association, the lower end of the grommet is upset or riveted over to form a bottom retaining iiange or head 29 partly recessed into plate 21. The upper iiange or head 26 nts loosely within hole 2li in the upper rule section, but serves a further .purpose than merely to house the mentioned head 26.

Ordinarily, a lmore or less iiat leaf spring is mounted within the rule joint in order to introduce a constant resilient ,friction 'between the hinge or strike plates tending to seat the male locking projections I5, l in the corresponding seats or recesses 2B, 20. Such a leaf spring is sometimes rather stiff and Vmay lose its power to retain the joint in stable open or closed condition, and the invention now involves the use of an entirely diierent form of spring.

Surrounding the upper portion of the grommet 25 beneath its head 2.6 is a coil spring 30 resting upon hinge or strike plate I4 of upper rule section S, resiliently urging this plate down into a resilient rictional contact with lower plate I'I on rule section II). The resilient reaction is provided by the grommet head Y2i; confining the upper end of the coil spring vwhile the latter rests onplate .I4 and this plate in turn rests on lower plate I'I,and plate iI rests on lower rule section -I whichis held with an upward bias by the bottom-finishing plate 2l retained upon grommet 25 by its lower upset or riveted end 25. Thus the active par-ts are kall retained between the upper and lower flanges or heads 26 and 29 of this lgrommet while vspring 30 introduces the resilient factor therebetween.

The result is thatupper plate is held with a given amount of pressure on lower plate I?! so as to ensure the rseating, .of male projections in female seat portions 20, 28 in .lower plate Il in fully open and also in fully closed position of one rule section with respect `to the other.

As the upper Vhead 2B of the grommet if left exposed to view in clearance hole 24 of upper rule section would be unfinished and unsightly in appearance, a second upper finishing plate SI is centered over hole 24 and secured `in place by two anchoring teeth 32, 32 driven into the wood of upper rule section 8, thereby concealing the head 255 of the grommet as well as spring 3B and generally covering hole 24 and making the upper side of the joint as a whole resemble the lower side of this joint having the ,lower iinishing plate 21, the upper plate having a hole 33 to imitate the open lower end of the grommet and its lower finishing plate 2T.

It has been stated that spring 3U is a coii spring, this including any true helix or frustoconical form of spring, as desired.

If spring 30 in Figure 2 is closely scrutinized, it will be seen that it may be considered substantially frusta-conical in form as it is wider at the lower end than at the top. In any case, the Yspring occupies the hole 24 only and does not extend clown into any portion of the lower rule section I0, being retained between hinge plate I4 and the upper flange 26 of grommet 25 beneath upper plate 3|.

It is, `of course obvious that we may make the rule sections of wood, plastic or light metal, while the hinge or strike plates may be made of brass, steel or any suitable metal or alloy, which is valso true of the spring, grommet and finishing plates. Naturally, the dimensions and proportions ofthe parts may be altered to suit any special conditions and we are of course not limited as to materials or dimensions, but the principle remains, namely that the coil spring is included in the rule joint for introducing a particularly advantageous resiiient effect allowing smooth opening and closing of the rule joint thus equipped. We may also maize the rule involved of as few or of as many rule sections as may be desired, .each joint being in form and construction similar to what has already been described hereabove.

Manifestly, variations may be resorted to, and parts and features may bemodiiied or used without others within the scope of the appended claims.

Having now fully described our invention, we claim:

l. In a vfolding rule having a pair of rule sections and a pair of hinge or strike plates individually secured upon said rule sections with a male lock projection upon one plate and the other plate having a female seat .portion therefor, the combination of a pivot nipple upon one plate, the other plate having a corresponding pvot hole into which the nipple projects and both rule sections having clearance holes concentric with said nipple, but the clearance hole in the rule section vcarrying the plate with the pivot nipple being greater in internal diameter than that of the other hole in the other rule section, a grommet 'extending `down through the nipple and having a. head upon one end within the greater hole, Va, coiled compression spring surrounding the grommet within the larger hole `beneath the grommet head, a iinishing plate mounted extremely of the relatively-smaller hole with the grommet extending thru said finishingv 'plate and being riveted over the latter upon the exterior thereof, and means fixed upon the rule section with the larger hole for covering thelatter and concealing the grommet head and coil spring therein. 1

2. A resilient folding rule hinge according to claim 1, wherein the means for concealing'the hole in which the grommet and coil spring are located includes a second finishing plate covering said hole and having anchoring teeth directed inward and driven into the material of the rule section upon which said platey is mounted, further anchoring teeth being directed inward from the finishing plate associated with the riveted end of 'the grommet into the material of the other rule section, 'the second .finishing plate corresponding to and resembling the said nishing plate associated with the riveted end of the grommet and centered with respect to said grommet.

3. A resilient folding rule hinge according to claim 1, wherein the coil spring is substantially helical in form.

4. A resilient folding rule hinge according to claim 1, wherein the spring is substantially frusto-conical in form.

5. A resilient folding rule hinge according to claim 1, wherein the coil spring and the grom' met head are located in the hole of one rule section and the nipple of the strike plate of said rule is directed away from the spring into the hole in the other strike plate and rule section in a. direction opposite to said spring, the spring resting upon the rst mentioned strike plate carrying said nipple and being located exclusively in the greater hole of the tWo holes in which the grommet is located.

5 HERMAN M. GASSTROM.

JOHN E. GASSTROM.

References Cited in the le of this patent UNITED STATES PATENTS 10 Number Name Date 1,900,640 Gasstrom Mar. 7, 1933 FOREIGN PATENTS Number Country Date 15 98,106 switzerland Mar. 1, 1923 

